Hillary Clinton has pneumonia. Five million to 10 million other Americans will also come down with the infection this year, but that’s no matter: Hillary Clinton is sick and is proving her weakness to the world and her unfitness to serve as president of the United States.

At least that’s what the alt-right wants you to think about the relatively benign diagnosis of a relatively common infection. For weeks, various fringe groups have been raising questions about the coughing they’ve heard emerge from the candidate’s mouth on several occasions. Trump tweeted that both campaigns should “release detailed medical records.” And now, though Clinton’s own doctor has disclosed that “she became overheated and dehydrated” at this weekend's September 11 event in New York—at least partially due to the diagnosis of pneumonia—a piece of news that wouldn’t worry you if it were about your own grandma has every national magazine and newspaper in its thrall.

The relentless conspiracy-theorizing about Clinton’s health—which started years ago, after Clinton sustained a concussion and “required six months of very serious work to get over” it, according to her husband—has swiveled an awful lot of heads in her direction now that a concrete statement about her health has been released. But the fact is, there’s a pretty simple reason why Clinton has caught a bug, and a pretty simple reason why she didn’t disclose it on Friday after she received her diagnosis.

Try to imagine Clinton’s average day: She has admitted that she sleeps only a few hours a night, telling Andrea Mitchell last year, “Don’t get enough of it, always want more of it.” She shakes hands with dozens, if not hundreds of people per day, and it’s difficult to imagine there is hand sanitizer tossed her way between each and every grip. Clinton often flies multiple times a day, with campaign stops in multiple states. And at various venues she must touch a whole host of germy handrails and bacteria-covered doorknobs. Anyone on the road with the same frequency would surely encounter more than a few sniffles and coughs along the way.

Add to that the utter exhaustion of campaigning—of being “on” at nearly every minute of the day, of moving from briefing to meeting to rally to briefing to plane to rally to briefing—and it’s entirely understandable why, once exposed to the virus that’s inflaming her lungs, Clinton got knocked down by it. It’s actually pretty simple: there is no such thing as a presidential immune system.

And for anyone wondering why she simply didn’t explain to the world that she has pneumonia the moment she found out: yesterday, on the 15th anniversary of September 11th, more attention was paid to Clinton’s near-faint than the lives of those lost in the worst attack on U.S. soil in history. Blame it on the election year, but that's a trend we hope won't continue.